Switch for electric ranges



H. W. BATCHELLER SWITCH FOR ELECTRIC RANGES Aug. 4, 1953 2,647,962

iled Jan. 11, 1950 2 Sheets-Sheet l INVENTOR HUGH W. BATCHELLER K 25 w wAT T'Ys 1953 H. w. BATCHELLER 2,647,962

SWITCH FOR ELECTRIC RANGES iled Jan. 11, 195C 2 Shee'.ts-Sheet 2 ii$k ili g Z15 :115511225.

s R P Mr W"- HIGH HIGH HIGH INVENTOR \GT 'HUGH w. BATCHELLER PatentedAug. 4, 1953 SWITCH FOR ELECTRIC RANGES Hugh W. Batcheller, Newton,Mass, assignor to Ark-Les Switch Corporation, Watertown, Mass., acorporation of Massachusetts Application January 11, 1950, Serial N0.138,021

Claims. 1

This invention relates to electric switches of the type suitable forservice in electric ranges in which the heating units consist of twosepa rate resistance elements adapted to be connected through the switchin various ways to power lines so as to make available several differentdegrees of heating. A considerable number of such switches have alreadybeen designed and produced. The object of the present invention is toprovide a switch of compact structure to save space and materialswithout sacrificing any of the qualities necessary for satisfactoryservice.

As hereinafter described in more detail, a considerable saving of spaceis had by arranging a series of bridging conductors in a row within ahousing member of insulating material, these conductors being strips ofspring metal which are fixed at one end, their free ends normallypressing against fixed contact elements. These strips are arrangededgewise to the rear wall of the housing. The free ends of all thebridging conductors press in the same direction against their contactelements, from which they are selectively disengaged by a rotatable dischaving cam elements on a face thereof cooperating with cam followersprojecting from an edge of the bridging conductors.

Further economies in cost and required space are had by the completeelimination of separate fastening elements such as rivets, bolts andscrews, except for the threaded hollow stem which projects from thecover plate and receives a nut by which the switch may be secured to asupporting wall or panel.

The metal parts within the housing are nearly all sheet metal stampings,the fixed conductors extending through slots in the rear Wall of thecasing to project as terminals to which wires are to be connected whenthe switch is installed in a range or elsewhere fOr use.

For a more complete undertsanding of the invention, reference may be hadto the following description thereof and to the drawings, in whichFigure 1 is a side elevation of a switch embodying the invention;

Figure 1A is a fragmentary section view similar to Figure 1;

Figure 2 is a rear elevation of the same;

Figure 3 is a front elevation of the housing member which supports theswitch elements;

Figure 4 is a section on the line 4- of Figure 3;

Figure 5 is a section on the line 5-5 of Figure 3;

Figure 6 is a section on the line 6- 6 of Figure 3;

Figure '7 is a section on the line 1-1 of Figure 1;

Figure 8 is a fragmentary section on the line 88 of Figure 1;

Figure 9 is an isometric view of the rear side of the cam disc, on alarger scale;

Figure 10 is a section on the line Iii-40 of Figure 9;

Figure 11 is an isometric view of a terminal member and bridgingconductor to be secured thereto, shown on an enlarged scale;

Figure 12 is a sectional view of the complete switch, the section beintaken on the line l2-|2 of Figure 13;

Figure 18 is-a section on the line l3l3.of Figure 12;

Figures 14, 15, and 16 are isometric views of three of the terminalmembers employed in the switch; and

Figure 17 is a diagram showing the off position and the seven onpositions of the switch in connection with a three-wire power line andtwo heating units.

As indicated in Figures 1 and 2, the switch comprises a housingconsisting of a rectangular housing member 29 and a front cover plate 22which, with the member 20, encloses a chamber. The cover plate isprovided with tongues 23 at its corners to be bent under exteriorshoulders on the member 20 to hold the cover in place. Projectingthrough the front cover plate is a tubular stem 24 which is externallyscrew threaded to receive a nut 26 by which the switch may be secured toa vertical wall or panel (not shown) through which the stem 24 mayproject. Journalled in the stem 24 is an operating shaft 28 on the outerend of which is mounted a suitable knob 30.

The housin member 20 may be a single molded unit of insulating material,the front elevation'al View of this member being shown in Figure 3. Thishousing member is generally rectangular in shape and comprises sidewalls 32, a top wall 34, a bottom wall 36, and a rear wall 38. In therear wall 38 are a series of narrow parallel slots 40 near one end ofthe member 20. Through these slots project a series of fixed sheet metalterminal members as hereinafter described. The rear wall 38 also has asecond series of slots 42 through which project other sheet metalterminal members. Projecting down from the top Wall 34 and forward fromthe rear wall 38 are a series of partition members 44, 46, and 48. Thesemembers are between successive slots 40 and serve as barriers betweenthe conductors or terminal members which project through these slots.The central barrier 48 extends down a little over half the length of themember 28 and is provided with a short cylindrical button as whichprojects for ward from the lower end of the front surface thereof. Thisbutton serves as a bearing element for a cam disc which is illustratedin Figure 9 and is hereinafter described in more detail.

Projecting through the slots ii are a series of sheet metal terminalmembers 52, one of which is illustrated in Figure 11. This memberconsists of a portion 54 a little wider than the length of the slot 40and an intermediate portion 56 having a width substantially equal to thelength of a slot 40. In the side edges of these two por- Y tions of theterminal member 52 are a pair of shoulders 58 which engage the innerface of the rear wall 38 when the small end 6 of the memher is thrustthrough a slot 48 so as to project out behind the rear wall 38. Thisprojecting portion 68 then serves as a terminal to which a wire is to beconnected when the finished switch is installed. The width of theportion 60 is less than that of the intermediate portion 55 so that apair of shoulders 62 are formed in the side edges between theseportions. The length of the midportion 56 is slightly greater than thethickness of the rear wall 38 at the slot 40. Hence when the member 52is thrust through a slot 48, the shoulders 62 project slightly beyondthe outside surface of the rear wall of the housing member. When themember 52 is in such position, it may be secured in place by staking.This is done by making wedge cuts at the shoulder 62 so as to spread theadjacent edge portions of the intermediate part 56 away from each otherforming edge shoulders it which engage the outer surface of the member25 so that the terminal is permanently secured in place.

To each of the four terminal members 52 is permanently secured anelongated resilient element. As shown, each such element is a bridgingconductor consisting of a strip of spring metal such as bronze. Asindicated in Figures 7 and 12, there are four such bridging conductorsE38, 68, i9 and ":2. Each of these conductors is permanently secured toits corresponding terminal member at right angles thereto so as toextend along the rear wall of the housing member 2%) toward its otherend. 'Any suitable means for securing the spring strips to theirterminal member may be employed. For simplicity and conenience, a coupleof tubular extrusions l may be made from the portion 54 of each terminalmember 52 which is to be within the housing. Corresponding holes 16 areprovided in each spring strip as illustrated in Figure 11 to receive thetubular extrusions 1d. The portions of the latter which project throughthe holes it are then clinched like hollow rivets to secure the strip tothe terminal member. The spring strips are each secured at one end, theother end being free. In a hole 28 in this free end is permanently fixeda suitable contact element 83 as is customary in switches to avoidexcessive deterioration of the switch elements by sparking the points ofcontact.

Also mounted in the housing member 25) are a number of contact elementssome of which are normally engaged by corresponding elements in the freeends of the spring strips. These contact elements are mounted in fixedterminal members such as are illustrated in Figures l4, l5 and 16. Theterminal member shown in Figure it consists of a sheet metal member 82having a portion 84 projecting through one of the slots 62 in the rearwall 38 of the housing member. The interior portion of the member 82 isT-shaped and lies against the bottom of a shallow depression 88 in theinner surface of the rear wall 38 and the arms of the T are bent up asat 88 so as to project forward, as indicated in Figure 12, forengagement by the free ends of the bridging conductors 6% and '52. Afixed terminal member Eii! is shown in Figure 16, this member having aU- shaped portion within the housing member 20 which projects forwardfrom the rear wall, the arms 92 and 94 of the U-shaped member each beingprovided with a contact element 83. A third fixed terminal 935 ismounted on the rear wall 38 with a portion 84 projecting through one ofthe slots 42. The interior portion 98 of this memher is bent at rightangles to the projecting portion 8 so as to rest against the bottom of arecess in the rear wall 38. The member also has aninner portion I52which projects forward from the rear wall and is located midway betweenthe arms 52 and 9 1 as shown in Figure 12. The spring strips 68 and T0are so arranged that the contact element at the free end of the formeris disposed between the arm 92 and the terminal element [02, and thefree end of the strip 18 is between the arm 94 and the terminal elementm2. All four of the spring strips 58, 63, "i9 and 12 are in planes whichare perpendicular to the rear wall 33 and extend from one end of thehousing member toward the other end so that they flex in a planeparallel to that of the disc. These strips are biassed to press againstrespective fixed contact elements in the same direction. As shown inFigure 12, this direction is toward the left. Thus the contact elementat the free end of the spring strip '12 normally presses against one ofthe contacts 88. The free end of the strip "Hi normally presses againstthe arm G l but is movable therefrom over into contact with the contactI02. The end of the strip 68 normally presses against the contact Hi2and is movable therefrom to engage the arm 82. The end of the strip 56normally presses against the other contact 83. Displacement of any ofthese spring strips from engagement with the corresponding fixed contactelements requires, as in Figure 12, movement toward the right. Thismakes possible a very compact arrangement of bridging conductors andterminals. In order to insulate the interior portions of the terminalmembers 82, 9G, and 99 from each other and from the spring strips, athin plate 164 of insulating material is placed over the portions of theterminal members which are displaced in the recesses and me.Furthermore, partition elements ill? and W8 are provided to separate thearms E32 and E i from the respective contact elements 38.

For the operation of the switch by moving the bridging conductors sothat their free ends are selectively separated from the respective fixedcontact elements which they normally engage, a cam disc Hi) is provided.This disc has channels I 12 and I [4 in its rear face, these channelsdefining cam elements projecting from the rear face of the disk, theside walls of which elements are cam surfaces engaged by cam followers Iit. The latter project forward from each bridging conductcr at a pointbetween the fixed and free ends thereof. As indicated in Figure 11, thecam follower of each bridging conductor may conveniently be integraltherewith. This can be done by forming a projection from a Side edge ofthe strip when the blank therefor is cut or punched from a sheet ofmetal. The strip is then reversely bent at the point where the lateraltongue projects from the side edge therefrom, the tongue also beingreversely bent so as to be in the shape of a partial cylinder. Thisgives it stiffness. This partial cylinder H6 is the cam follower whichbears against a corresponding cam surface on the disc H0. For rotatablysupporting the disc a central bore 12c is provided therein, this borebeing just large enough at the rear face of the disc to fit on thebearing pin 5 The other end of the bore is larger and is of a nonroundshape to receive a similarly shaped end 122 of the operating shaft 28which is journalled in the stem 24. Thus the disc is keyed to the shaftso as to be positively rotated thereby when the shaft is turned byoperation of the finger knob 30. As shown in Figure 1A, the disc isdisposed immediately behind the cover plate 22. The spring strips aredisposed between the disc and the rear wall 38 and edgewise to both. Inthe rim of the disc H0 are a series of eight notches I30 which areequally spaced around the circumference of the disc. These notchescooperate with a pair of spring elements I32 which are disposed withinthe side walls 32 of the housing member. The elements I32 rest againstshoulders I34 within the side walls of the housing member and are formedwith a central boss I 36 adapted to enter the notches I30. When the discis turned, the springs I32 yield to allow the bosses I36 to ride out ofthe notches I30 in which they are engaged. These notches thus serve todefine eight angular positions of operation of the disc, these severalpositions being illustrated in Figure 17.

The grooves H2 and H4 in the rear face of the disc form four generallycircular cam surfaces which are perpendicular to the plan of the disc,some of these surfaces being interrupted to save material and simplifythe process of molding the disc. The sides of the outer groove II2constitute cam surfaces I42 and I44. The shape of the cam surface I42determine the operation of the bridging conductor 12. The shape of thecam surface I44 determines the operation of the bridging conductor 60.The sides of the inner groove I I4 constitute generally circular camsurfaces I46 and I48, the cam surface I46 serving to operate thebridging conductor 19, the cam surface I48 serving to operate thebridging conductor 68. The cam surfaces ally inward. The cam surfacesI44 and I48 face radially outward. Figure 17 illustrates a typicalcircuit wherein the switch may advantageously be employed. This circuitincludes a three wire power supply from which the usual 110 volts and220 volt can be obtained. By means of the switch these power lines areselectively connected to one Or both of a pair of resistance heatingunits I50 and I52. A pilot light I54 is also provided, this pilot lightbeing on when either of the units I50 and I52 is connected to the powerlines.

I claim:

1. An electrical switch comprising a housing member of insulation havinga rear wall with a plurality of narrow slots therethrough, a front covermember secured to said housing member, a shaft journalled in said covermember, a cam disc keyed to said shaft within the housing, sheet metalmembers extending through said slots, the exterior portions of saidmetal members serving as terminals, each said metal member havingshoulders against the inside and outside of said rear wall to secure themember in place, fixed contact elements on the inner portions of some ofsaid metal members, spring strips secured at one end to other of saidmetal members, said strips being arranged between said disc and rearwall and edgewise thereto, each said strip having its other end normallypressing against a respective contact element, cam means on the rearface of said disc, and means on said strips cooperating with said cammeans to move said strips selectively out of engagement with theircontact elements when the disc is rotated.

2. An electrical switch comprising a housing member having a rear wall,a series of four conductors mounted in said housing near an end thereofin planes perpendicular to said rear wall, spring metal strips securedat one end to respec- I42 and I46 face raditive conductors and extendingtoward the other end of the housing member, a fixed terminal member nearthe other end of said housing having a U-shaped portion with contactelements in the arms of the U, a second fixed terminal member having acontact element between and in line with the contact elements of thefirst said terminal member, the free end of one of said spring stripsbeing arranged to press normally against one of the contact elements ofthe first fixed terminal member and to be movable therefrom into contactwith the contact element on the second fixed terminal, the free end of asecond spring strip being arranged to pres normally against the contactelement of the second fixed terminal and to be movable therefrom intocontact with the other contact element of the first fixed terminal, athird fixed terminal member having spaced contact elements normallyengaged by the free ends of the third and fourth spring stripsrespectively, and cam means for selectively moving said free ends awayfrom their respective contact elements.

3. An electrical switch comprising a housing member of insulation havinga rear wall with a plurality of narrow slots therethrough, a front covermember secured to said housing member, sheet metal members extendingthrough said slots, the exterior portions of said metal members servingas terminals, each said metal member having inner shoulders on its edgebearing against the inner face of said rear wall and outer shoulders onits edges bearing against the outer face of said rear wall, the pointsof engagement of said shoulders with the rear wall being at the ends ofthe slot through which the metal member projects, switch elementssecured to said sheet metal members within the housing member, fixedcontacts in said housing member engageable by said switch elements, andcam means operable to move said switch elements with reference to therespective contacts.

4. An electrical switch comprising a rotatable disc, a plurality ofupstanding cam elements on a face of said disc having cam surfacesperpendicular to the plane of said face, said cam surfaces beinggenerally circular and variously spaced from the axis of the disc, aplurality of elongated resilient members arranged in a plane paralleland adjacent to said disc and flexible in said plane, each said flexiblemember having a cam follower extending therefrom toward said disc andengageable by respective said cam surfaces as the disc rotates wherebyto flex said flexible members, means rotatably supporting said disc andmaintaining said flexible members in operative relation to said disc,and contact elements carried by said means and flexible members formutual engagement and disengagement when said flexible members areflexed and unflexed.

5. An electrical switch as in claim 4, at least one of said cam surfacesfacing radially inward and at least one facing radially outward.

HUGH W. BATCHELLER.

References Cited in the file of this patent UNITED STATES PATENTS

